Dumb-waiter door and cam operator



3" 195 3 1 L. Mc U DUMBWAITER DOOR AND CAM OPERATOR gwwm 3 Sheets-Sheet1 Filed June 26, 1948 IIIIIIIIIIIIIIIIIIII.

INVENTOR. ARTHUR L. MCI \EA UL,

ATTO F/VFXS Jan. 31, 1950 MGKEAGUE 2,495,902

DUMBWAITER DOOR AND CAM OPERATOR Filed June 26, 1948 v 3 Sheets-Sheet 2INVENTOR. ARTHUR LMCKEAGUL A T f/VEYS Jan, 31, 39% A. L. M KEAGUEDUMBWAITER DOOR AND CAM OPERATOR 5'SheetsSheet 5 Filed June 26, 1948 x?)J l INVENTOR. ARTHUR LMCKEA GU11 BY L Patented Jan. 31, 1950 DUMB-WAITERDOOR AND CAM OPERATOR Arthur L. McKeague, Staten Island, N. Y., as-

signor to Syncro Machine Company, Perth Amboy, N, J a corporation of NewJersey Application June 26, 1948, Serial No. 35,505

13 Claims.

The present invention relates to means for operating the doors of adumbwaiter, and particularly to a means for operating: the doors whichutilizes a torque motor and which causes opening movement of the doorswithout shock.

More particularly still, the invention relates to such dumbwaiter dooroperating units which may also operate the retiring cam in timedrelationship with the door opening and closing movements, this retiringcam controlling the unlatching of the shaft doors in the usual manner.

More particularly still, the invention relates to a mechanism to effectthe combined functions of operating a dumbwaiter door and a retiring camwhich mechanism is effective to initiate door and retiring cam operationsimultaneously and to complete the door opening movement after theunlatching of the shaft doors by the retiring cam.

Additionally, the present invention provides an overrunning clutch and aspring to assure that the doors in their movement will not rebound andcause strain in the unit.

It is an object of my invention to provide a dumbwaiter door operatorvhaving means for automatically opening and closing the doors and beingprovided with means for assuring that the door movements will be withoutimpact, said operator including a torque motor.

It is another object of the invention to provide such a unit whichlikewise controls the operation of the usual retiring cam.

It is another object of the invention to provide a door operating unitin which the movement of the retiring cam is of a standard amount andthe movement of the door operating mechanism is adjustable to adapt theunit to dumbwaiters having different heights and resulting diiferentlydimensioned doors.

It is a further object of the invention to provide a door and retiringcam operating unit in assuring that the shaft doorways are unlatched;

at the time when the car doors reach their fully open position. Inclosing the withdrawal of the retiring cam is initiated when the cardoors are nearly closed and thus the shaft doors are latched slightly,before the car doors reach their fully,

closed position.

It is a still further objectof the invention to provide such a unitwhich is readily mounted up on the dumbwaiter and readily connected foroperation ofthe doors and the retiring cam.

- dumbwaiter frame.

Other objects and features of the invention will become apparent whenthe following description is considered in connection with the annexeddrawings, in which:

Figure 1 is a front elevation of a dumbwaiter having the door andretiring cam operator of my invention mounted thereon and connected foruse;

Figure 2 is an enlarged fragmentary sectional view of the door and camoperator of Figure 1, the section being taken on the plane of the line22 of that figure;

Figure 3 is a developed cross-sectional view of the device of Figure 1;

Figure 4 is a fragmentary view of the unit of my invention, with thehousing partly broken away, showing particularly the construction of therebound eliminating means; and

Figure 5 is a fragmentary view showing the mode of attaching the dooroperating chain to a bracket which is in turn fixed to the door.

The dumbwaiter is generally indicated at In in Figure 1. On top of thedumbwaiter structure there is mounted the door and cam operator of thepresent invention, being generally designated H. The dumbwaiter doorsare of the center operating type, vertically movable, and are here shownat 12 and i3. The upper door I2 is connected bymeans of a bracket [4 tothe center portion of a turnbuckle I5, which is in turn connected at itsends to the ends of a chain Hi. The chain I 6 is in effect an endlesschain, due to the connection of its ends by means of the turnbuckle l5,and is driven by the sprocket wheel I! in a manner to be hereinafterdescribed.

This chain also passes over the idler sprocket l8 which is suitablymounted in an upper frame member 2!] of the dumbwaiter structure.Sheaves may be substituted for the idler sprocket l8 as well as for thesimilar idler sprockets 23 and 25 hereinafter described.

The retiring cam 2| is suspended from a chain 22, which chain, in theusual manner, passes over a sprocket Wheel 23 rotatably mounted on theThe chain 22 cooperates with the operating mechanism in a manner whichwill be hereinafter described. As has been indicated above, the retiringcam operates to unlatch the shaft or hatchway door at which thedumbwaiter has been stopped. The details of this operation need not behere described since they are Well known in the art.

The lower door l3-is connected to the upper door [2 and operatestherewith, although in,the opposite direction. This operation is broughtdesignated 28. The shaft 26 is driven by means of a torque motor 30, i.e. a motor which can be stalled across the line for varying amounts Suchmotors are known in the art and.

of time. are rated in foot pounds of torque and in the percentage oftime that they canbe stalled'with' power connected. Thus a duty motorcan be stalled with power on for six minutes out of every hour. wouldpreferably be one of 50% rated duty. The torque motor 36 drives shaft 26through the medium of a pair of sprocket wheels, one being mounted onthe motor shaft and one on shaft 26, the latter being designated 3I, anda chain 32 passing over these sprocket wheels.

Fixed to the shaft 26 for rotation therewith is a. pinion 33 whichcooperates with a gear 34 rotatably mounted on shaft 35, the lattershaft being likewise supported in bearings in the front and rear plates21. Gear 34 is free to'rotate upon shaft 35 and has connected with itthe outer member 36 of an overrunning clutch, the inner member 31 ofwhich is keyed to shaft 35, this overrunning clutch being of a commonform and consisting of a toothed drum having rollers in the toothspaces, as is well known in the art. Likewise keyed to shaft 35 is apinion 38 which meshes with a gear 40 keyed to shaft 4I, this shaftbeing likewise supported in bearings in the front and rear plates 21.

Fixed to shaft M for rotation therewith is a sprocket wheel I1,previously described (see Figures 1 and 2) which operates the doors I2and I3. In a particular embodiment the sprocket dimensions are such thatthe doors travel ten inches for each rotation of sprocket wheel I1 andthe motor speed and gear ratios are such that the doors move at a rateof approximately eight inches per second.

In order to provide that the hatch doors be unlocked during the finalopening movement of the dumbwaiter doors I2 and I3, a time delaymechanism in the form of an escapement washer is provided.

This escapement washer comprises a disc or plate 42 rotatably mounted onshaft 4| and carrying a pin 43 extending laterally thereof adjacent itsperiphery.

Adjacent washer 42 and to its right, as seen in Figure 3, is a sleeve 44which carries sheaves 45 and 46. Sleeve 44 is mounted in a bearing inplate 21 and shaft M is in turn rotatably supported in the sleeve.Mounted radially in the hub 41 of gear 40 is a pin 48 which pin in itsrotation will strike pin 43. Extending radially from sleeve 44 is a pin56 which lies in the path of rotation of the pin 43.

Thus as shaft 4I turns washer 42 will remain fixed for a predeterminedfraction of a turn after which it will be forced to rotate with theshaft. Similarly after washer 42 starts to rotate a predeterminedfraction of a turn will be traversed before pin 43 strikes pin56;thereafter the sleeve 44 will rotate with the shaft.

The motor used in this instance 4 Sheave 46 operates the retiring camthe connection therebetween being by means of chain 22 which is fastenedto the sheave by means of pin 53 in a manner clearly indicated in Figure3.

In like manner, a chain 52 is fastened to sheave 45 by a pin 5|. Theopposite end of chain 52 is suitably fastened to a rod 54 guided in a Ushaped bracket 55 and upper portion of housing 28. Rod 54 is providedwith a washer 56 which limits its upward movement and a compressionspring51 extends between bracket 55 and nut 58 on the threaded end ofthe rod. Thus during movement of sleeve 44, the spring 51 iscompressedservingas a clamping device to check the last few inches ofdoor travel and to eliminate strain and rebound in the unit. This springalso serves to initiate the opening movement of the doors when power isremoved from the motor 30.

The details of the connection of chain I6 to the door are shown inFigure 5. Reference to this figure will show that the angle bracket I4is connected to a turnbuckle I5 at a predetermined position thereon bymeans of the nuts 60 and washers 6I. Each end of chain I6 is providedwith an offset collar 62 into which one end of the turnbuckle extendsbeing held in adjusted position by means of nuts 63.

As will be apparent from the foregoing description, circuits of'knowntype are provided so that when the dumbwaiter arrives at a predeterminedfioor the power to the torque motor is shut off. Thereupon the doorsstarting opening due to the energy stored in spring 51 (Figure 1)acting'through pin 52 andcausing sheave 45 (Figure 4) to rotate in adirection to open the doors. The rotation of sheave 45 (Figure 3) causessleeve44 and sheave 46 to also revolve. The rotation of sheave 46 causeschain 22 (Figure 1) to unwind and the retiring cam to thus be advanceddue to the action of a spring incorporated'in-the retiring cam as wellas by gravity in the usual manner.

As sheave45 rotates the-pin 56 bears against pin 43'inmember 42 which inturn bears against pin 48 in thehub 41 of gear 40. Since gear 46 iskeyed to the shaft II, the sprocket wheel I1 is also caused to rotateand this motion is transmitted through chain I6: to the upper doorcausing it to move in an opening direction. The completionv of openingmovement of the doors is brought about due tothezfact that the lowerdoor is heavier than the upper one. Thus the shaft. 4|: continues torevolve after sleeve 44 has been stopped resultingin separation of thepins 48 and 43 from driving connection with the pin 50. The doormovement continues until the upper door is stopped by the rubber bumpers65 on the door guides 64..

A11 rotation of shaft 4I (Figure 3) and of gear 40 is, of course,transmitted through pinion 38 to the overrunning clutchv 3631 andthrough it to gear 34, pinion 33 and sprocket 3I to the torque motor 30(Figure 1) causing the motor to rotate in a reverse direction. When theupper door is stopped as described. all rotating parts back to theclutch member 31 also stop. However, the use of the overrunning clutchpermits the motor armature and sprocket 3 I, pinion 33, gear 34 andmember 36 of the overrunning clutch to continue to revolve and thusprevents sudden dissipation of the kinetic energy stored in the rotor ofmotor 30. In this way the overrunning clutch prevents the energy of themotor armatur or rotor from being trans mitted to the doors and thusprevents excessive impact of the upper door against stops 65 (Figure 1).

Due to the use of a torque motor operated as described, the dumbwaiterdoors are opened and the hatohway doors unlatched upon a power.

failure and thus access to the shaft and dumbwaiter permitted.

When the dumbwaiter is called to another floor, the torque motor isenergized. After considerable movement of the motor and the doors therotation of gear 40 brings the pin 48 into contact with pin 43 of member42 and thereafter contirmcd rotation brings pin 43 into contact with pin59 whereupon rotation of sleeve 44 commences. Thus the retiring cam isretracted during the last portion of the closing movement of the doorsand likewise during this last portion of closing movement the spring 5'!is compressed.

While I have described a preferred embodiment of my invention, it willbe understood that modifications thereof may be utilized within thescope and spirit of my invention. Consequently, I wish to be limited notby the foregoing description but, on the contrary, solely by the claimsgranted to me.

What is claimed is:

1.. An operator for the car doors and retiring cam of a dumbwaitercomprising, in combination, a torque motor, a gear reduction unit drivenby said torque motor, an output shaft driven by said reduction unit,said output shaft being operatively connected to the car doors, anescapement washer driven by said output shaft, and means driven by saidescapement washer for operating said retiring cam, whereby said retiringcam advances during the initial movement of said car doors to openposition and retreats during the final movement of the doors to closedposition.

2. An operator for the car doors and retiring cam of a dumbwaiter asclaimed in claim 1, characterized in that the position of saidescapement washer is adjustable to determine the proportion of the totalmovement of said output shaft which shall be effective on said retiringcam.

3. An operator for the car doors and retiring cam of a dumbwaiter asclaimed in claim 1, characterized in that said gear reduction unitcomprises an over-running clutch thereby permitting said torque motor torun free when the doors reach their final position preventing damage tosaid u.

4. An operator for the car doors and retiring cam of a dumbwaitercomprising, in combination, a torque motor, a gear reduction unit drivenby said torque motor, an output shaft driven by said reduction unit,said output shaft being operatively connected to the car doors, anescapement washer driven by said output shaft, means driven by saidescapement washer for operating said retiring cam, whereby said retiringcam operates during the final movement of said car doors to closedposition, a second escapement washer driven by said output shaft, springcushioning means, and means driven by said second escapement washer fortensioning said spring cushioning means to thereby damp the finalclosing movement of the car doors and said torque motor.

5. An operator for the car doors and retiring cam of a dumbwaiteraccording to claim 4, charaoterized in that said gear reduction unitoomprises an over-running clutch, whereby said torque motor may run freeof said output shaft during the final door opening and retiring cammovement.

6. An operator for the car doors and retiring cam of a dumbwaiteraccording to claim i, char- 5 acterized in that said torque motor, gearreduction unit and spring cushioning means are mounted on thedumbwaiter. 7. An operator for the car doors and retiring cam of adumbwaiter according to claim 4, characterized in that said secondescapement washer drives a sheave freely rotatable upon said outputshaft, said sheave being connected to said retiring cam by-a chain, andsaid second escapement washer also drivesa second sheave adjustably 15freely connected to said first sheave, said second 7 sheave beingconnected to said spring cushioning means by a chain.

8. An operator for the car doors of a dumbwaiter comprising, incombination, a torque motor, a shaft driven by said motor and drivingthe car doors, an escapement washer driven by said shaft in thedirection of door closing movement, spring cushioning means, and meansdriven by said escapement washer for tensioning said spring means todamp the final closing movement of the car doors and the torque motor,said tensioning of said spring means also providing an initial impulsetoward open position of the car doors when said torque motor isdeenergized.

9. An operator for the car doors of a dumbwaiter comprising, incombination, a torque mtor, a gear reduction unit driven by said torquemotor, an output shaft, driven by said reduction unit, said output shaftbeing operatively con nected to the car doors, an escapement washerdriven by said shaft in the direction of door closing movement, springcushioning means and means driven by said escapement washer fortensioning said spring means to damp the final closing movement of thecar doors and the torque motor, said tensioning of said spring meansalso providing an initial impulse toward open position of the car doorswhen said torque motor is deenergized.

10. An operator for the unbalanced vertically movable car doors of adumbwaiter comprising, in combination, a torque motor, a shaft driven bysaid motor and driving the car doors, an escapement washer driven bysaid shaft in the direction 50 of door closing movement, springcushioning means, means driven by said escapement washer for tensioningsaid spring means to damp the final closing movement of th car doors andthe torque motor, said tensioning of said spring 55 means also providingan initial impulse toward open position of the car doors when saidtorque motor is deenergized, the unbalanced door weight driving thedoors to open position, and an overrunning clutch operatively connectedbetween 50 said shaft and said torque motor, said clutch serving todisconnect said motor from said shaft upon the car doors reaching theirfully open position, whereby the inertia of said motor is not applied tosaid doors and impact of the doors is eliminated.

11. An operator for the car doors of a dumbwaiter comprising incombination, a torque motor,

a shaft driven by said motor and driving the car doors, an escapementwasher driven by said shaft 70 in the direction of door closingmovement, a

sheave driven by said escapement washer, a chain fixed to said sheaveand adapted to be wound thereon, a piston connected to said sheave and aspring coiled about said piston, said spring being 75 tensioned bymovement of said piston during final closing movement of the car doorsto damp the final closing movement of the car doors and the torquemotor, said tensioningof said spring means also providing an initialimpulse toward open position of the cardoors when said torque motor isdeenergized.

12. An operator for the car doors of, a dumbwaiter comprising, incombination, a torque motor, a gear reduction unit driven by said torquemotor, an output shaft driven by said reduction unit said output shaftbeing operatively connected to the car doors, an escapement washerdriven by said shaft in the direction of door closing movement, a sheavedriven by said escapement washer, a chain fixed to, said sheave andadapted to be wound thereon, a piston connected to said sheave and aspring coiledv about said piston, said spring being tensionedby movementof said piston during final closing movement of the car doors to dampthe final closing movement of the car doors and the torque motor, saidtensioning of said spring means also providing an initial impulse towardopen position of the car doors when said torque motor is deenergized.

13. An operator for the unbalanced vertically movable car doors of adumbwaiter comprising, in combination, a torque motor, a shaft driven bysaid motor and driving the car doors,,an escapement washer driven bysaid shaft in the direction of door closing movement, a sheave driven bysaid escapement washer, a chain fixed to said sheave and adapted to bewound thereon, a pistonconnected' to said sheave and a spring coiledabout said piston, said Spring being tensioned by movement of saidpiston during final closing movement of the car doors to damp the finalclosing movementof the car doors and the torque motor, said tensioningof said spring means also providing an initial impulse toward openposition of the car doors when said torque motor is deenergized, theunbalanced door weight driving the doors to open position, and anoverrunning clutch operatively connected between said shaft and saidtorque motor, said clutch serving to disconnect said motor from saidshaft upon the car doors reaching their fully open position, whereby theinertia of said motor'is not applied to said doors and-impact of. thedoors is eliminated.

ARTHUR L. McKEAGUE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,906,677 Waldman May 2, 19332,175,906 McCormick Oct. 10, 1939 2,458,402 Myers Jan. 4, 1949

